Urolithiasis is a common condition with increasing incidence worldwide [2]. Patients’ HRQOL was found to be decreased, particularly with respect to their physical and mental states [5, 6, 23–25]. Penniston et al. [7, 10] developed a stone-specific questionnaire, the WISQOL, with robust psychometric properties, which has been already translated and validated in different languages [11–15]. Worldwide, we are observing an increasing interest in publishing high quality papers on urolithiasis. In fact, Abedi et al. [26], during decade 2010–2020 if compared with the previous decade, reported an increased volume of publications corresponding to 133%, 103.5% and 70.4% for ureteroscopies, PCNLs and ESWL respectively. This fact highlights the need of tools to objectively report, analyze and compare HRQOL parameters. Therefore, in our opinion, the IT-WISQOL will provide an important support for this purpose.
This study demonstrates that IT-WISQOL is a reliable assessment tool for the evaluation of symptoms in patients suffering from urolithiasis. IT-WISQOL showed satisfactory validation results, with an excellent internal consistency across all domains (α ≥ 0.88), particularly when the total score is considered (α = 0.960). Similar results were also found with the original WISQOL [10] and the French version [13], both with a total score α = 0.970. The test–retest reliability showed good values for each domain, and excellent results for the total questionnaire (Pearson correlation value for total score: 0.85) (Table 1). Comparison with other studies is not easy as test-retest reliability has been measured with different tools, like Spearman rank correlation or Cronbach’s α in the German and Turkish validation study respectively [12, 14].
Inter-domain reliability analysis showed analogous results to other validation studies [10, 12, 13]. Consistently with previous works [10, 12, 13] we found a moderate correlation between the vitality domain (D4) and the emotional domain (D2) at 3-months follow up (Spearman’s rho correlation coefficient = 0.497), but not at preoperative and 30-days post-operative questionnaires. The reason for these findings remains to be clarified. According to Bhojani et al. [13] this weaker correlation suggests that patients with lower HRQOL in the context of nephrolithiasis also tend to experience higher levels of stress (Table 2).
Convergent validity of IT-WISQOL was confirmed by a good correlation with subdomains of the SF-36v2 measures (Table 2). Figure 1 shows how total score of IT-WISQOL and SF-36v2 were significantly correlated at any of the follow-up times the questionnaire has been administered. This makes IT-WISQOL a dedicated reliable tool and comparable with the Italian SF-36v2 questionnaire.
This is the first study aiming to evaluate reliability and adequacy of Italian version of WISQOL. The questionnaire demonstrated to be reliable if compared to other versions. We included 6 Centres located in different parts of Italy with different dialects and in all of them the questionnaire resulted to be adequately usable.
Our study has some limitations. First of all, the number of patients involved is limited. Studies using IT-WISQOL in larger populations are desirable. Additionally, most of patients had a high educational level, thus further testing on patients with low education may further improve readability of the questionnaire. Patients have been recruited in Academic centres, thus they might have more complex stone disease than general population, affecting our results. Furthermore, the study has been conducted during two COVID-19 outbreaks. This limited our capacity in recruiting patients and a certain amount of distress on patients could be expected, potentially affecting final results.